Suspected microcephaly cases in Brazil since October

The World Health Organisation says it expects the Zika virus to spread further throughout the Americas. +

It anticipates that the virus 'will likely reach all countries and territories of the region where Aedes mosquitoes are found' - Canada and continental Chile are the only countries in the region where Aedes mosquitoes are not present.

The WHO says local populations have not been exposed to Zika before and therefore lack immunity.

Speaking on Wednesday, WHO director general Dr. Margaret Chan said that while a causal link between the Zika virus in pregnant women and babies born with microcephaly had not been established, 'the circumstantial evidence is worrisome'. *

Microcephaly is a condition where babies are born with smaller than normal heads.